- Neutrexin
- neutropenia
- neutrophil
- nevoid basal cell carcinoma syndrome
- nevus
- Newcastle disease virus
- Nexavar
- Nexium
- NF1
- NF2
- NG tube
- NG-monomethyl-L-arginine
- NGR-TNF
- NHL
- niacin
- niacinamide
- nicotinamide
- nicotine
- nicotine gum
- nicotine inhaler
- nicotine lozenge
- nicotine nasal spray
- nicotine patch
- nicotine replacement therapy
- nicotinic acid
- NicVax
- Niferex
- nifurtimox
- NIH
- Nilandron
- nilotinib
- nilutamide
- nimodipine
- Nimotop
- nimotuzumab
- nimustine
- Nipent
- nipple
- nipple discharge
- nitric acid
- nitric oxide-releasing acetylsalicylic acid derivative
- nitrocamptothecin
- nitroglycerin
- nitrosamine
- nitrosourea
- Nizoral
- NK cell
- NK-LGL
- NK-LGL leukemia
- NK-LGLL